How can I make a glowing iris (eye) material similar to these pictures?
Here is a file and a screen shot - I extruded my circle and then applied scale and transformation (ctrl-A) before unwrapping the mesh and choosing Follow Active Quads and Even so that they would align liek you see in the lower left.
Then I made up a material to use a texture to stencil between the shaders to get emission area showing.

https://drive.google.com/file/d/1m-ZLTv5bUzeDT5XOHaVbgBRGhAtu8maB/view?usp=sharing